Where science meets application

Research Review: Muscle Activation in Catchers

The throwing motion is very similar across all positions. Research has shown time and time again that ALL energy is developed from the lower half of the body, gets transferred throughout the trunk and pelvis, which allows for the speed of the arm to accelerate during ball release.

Throwing kinematics are very similar between pitchers and catchers. However, the only difference is the magnitude of these kinematics.

As for the throwing arm, catchers have greater elbow flexion during the arm cocking phase of the throwing motion, and less forward trunk tilt [1].

If you want your catcher’s arm to stay healthy, their lumbopelvic control and gluteals need to be STRONG. The inability to control your pelvis and trunk results in an energy leak during the throwing motion, and leads to movement inefficiency.

The proximal-to-distal energy sequence states that during dynamic movements, energy is transferred from larger to smaller segments to maintain speed, force, and direction of force [1].

Gluteal Activation

The numbers that the researchers used to determine high-points in activation was the participant’s maximal isometric contraction. I think this is important to discuss.

Basically, before reading and interpreting the data, the participants had to push as hard as they could from their glutes to get a “maximal contraction”.

The participants then threw down to second base with EMG markers on them, and researchers could now read the maximal percentage of the contraction.

The stride leg (non-throwing side) has the greatest gluteal activity (70%) during the acceleration phase of the throwing motion. You don’t have to push AS hard as you can, just hard enough!

The drive leg also has the greatest gluteal activity during the acceleration phase.

The gluteus medius (hip) of the drive leg had the greatest activity during the arm cocking phase of throwing. This is the time between front foot contact and maximal external rotation.

This shows that catchers do need to get a good amount of extension from their back leg when popping up for a throw to second base. I see this as one of the biggest inefficiencies.

Pelvic and Trunk Activation

I think this was a pretty interesting way in starting off the results:

“The position of the pelvis was initially tilted toward the drive leg, but as the throwing motion progressed, the pelvis tilted toward the stride leg.”

Trunk rotational velocity was reported to be GREATER than pelvic rotational velocity. I think this makes sense because the catcher must move as quick as possible and get the ball 120 feet away to a very small target.

The gluteal muscle group is directly responsible for the dynamic stability of the pelvis [1].

In this study, the gluteals stabilized the pelvis by forming an “anchor point” for the trunk flexors to activate [1].

Discussion

Although the throwing motion from the mound consists of six different phases, the catching motion has two separate phases: The pop-up and the release.

In the first phase, the catcher must propel himself forward and outward by generating force from the back leg. The ankle, knee, and hip must all be inside each other to create what is known as “triple extension”.

While the back leg is driving, the stride (front) leg should turn open to allow for the hips to begin rotating. At front foot contact, the pelvis then becomes a stabilizer so that energy is transferred to the trunk.

The second phase is highlighted by arm cocking. This phase is between front foot contact and maximal external rotation of the shoulder. The greater the external rotation, the greater the velocity [1].

The gluteus medius acts as a dynamic accelerator and stabilizer. For pitchers, it reaches peak activity at maximal external rotation. For catchers, it reaches peak activity at front foot contact. According to this research, catchers may not be fully using trunk rotation at maximal external rotation.

Just like any other complex movement, I think it’s all about timing of the movements. The next underlying issue would be strength in a single leg stance, as well as generating power relative to bodyweight.

Isometric exercises work best for catchers to be able to get strong in a specific position.